The timey-wimey detector was a makeshift device used for detecting temporal anomalies by the Tenth Doctor. He used it when he was trapped in 1969 by the Weeping Angels to detect others who had been sent back in time. It looked like a late-20th century portable open-reel tape recorder with only one spool. It alerted the Doctor to an anomaly by dinging. The exact nature of the device's functioning was not made clear; the Doctor's deliberately vague explanation to Billy Shipton was that "it goes 'ding' when there's stuff." However, it may be inferred the timey-wimey detector was primed to detect residual artron energy acquired by beings who had travelled in the Time Vortex. This energy was loosely described by the Doctor as "wibbly-wobbly, timey-wimey stuff", hence the name of the device. The timey-wimey detector had one main side-effect: "It boils an egg at thirty paces, whether you want it to or not." The Doctor learned to stay away from hens, as "it's not pretty when they blow". (TV: Blink)
The device was later destroyed. (PROSE: Ghosts of India) The Eleventh Doctor presumably carries a new one, which he uses in another encounter with the Weeping Angels for the same purpose. (PROSE: Touched by an Angel)